Predictors of Mortality and Prolonged Hospital Stay after Diagnosis of Perioperative Myocardial Infarction in Patients Undergoing Isolated Coronary Artery Bypass Crafting

Objective: To determine predictors of mortality and prolonged hospital stay in patients presenting perioperative myocardial infarction (PMI) after CABG.

Methods: Between January 2006 and October 2013, 3,969 patients underwent isolated CABG in our institution. 190 patients (4.8%) underwent re-coronary angiography after clinical diagnosis of PMI. A search of risk factors for the composite endpoint including in-hospital mortality and prolonged hospital stay was performed through a logistic regression analysis. Severely prolonged hospital stay was defined as a stay of more than 30 days in our institution.

Results: In hospital mortality after PMI was 11.6% (22 of 190 patients), mean hospital stay was 17.5 days SD ± 18 days, 24 patients experienced a prolonged hospital stay. Graft related PMI involved LAD, RCX and RCA territories in 42, 23 and 17 patients respectively. Two vessel involvement comprised LAD + RCX territory (21 patients), LAD + RCA territory (10 patients) and RCA + RCX territory (9 patients). In 10 patients re-angiography showed flow impairment in all three vessels. 58 patients showed no impaired flow of grafts. Logistic regression analysis identified age (p = 0.005; OR 1.1), emergency admission (p = 0.006; OR 3.2), insulin dependent diabetes mellitus (p = 0.03; OR 3.0), an extended PMI of all three vessels (p = 0.02; OR 5.4) and need for operative graft revision (p = 0.0127; OR 2.0) as independent causes of the composite endpoint.

Conclusion: PMI after CABG generally results in a notably bad outcome in terms of mortality and prolonged hospital stay. Moreover the presence of the identified risk factors can further change the prognosis.